The present invention relates to a drain pipe connected with a canister system installed under the floor of a vehicle on which front seats are attached.
Conventionally a vehicle is provided with a canister system to contain an active charcoal functioning as an absorbent to have fuel vapor adsorbed, as indicated, for instance, by such references as Japanese Utility Model Registration No. 2582688, Japanese Laid-open Patent Application No. H09-49460 and Japanese Laid-open Patent Application No. 2005-313667.
There is a drain pipe attached to the canister body through which cleaned air after the fuel vapor is adsorbed and removed is to be discharged into the atmosphere and air in the atmosphere is to be taken in. Generally speaking the canister system for a vehicle is installed in either an engine room of a vehicle, under a rear seat floor of a vehicle or under a front seat floor of a vehicle as indicated, for instance, by such references as Japanese Utility Model Registration No. 2582688, Japanese Laid-open Patent Application No. H09-49460 and Japanese Laid-open Patent Application No. 2005-313667.
In the case of a canister system installed in an engine room, the canister body is fixed on a vehicle body on the front side of the dash board, as indicated, for instance, by Japanese Utility Model Registration No. 2582688. A drain pipe with a lower end open, which communicates with the atmosphere, is attached to the lower part of the canister body.
In the case of a canister system installed under a rear seat floor of a vehicle, a canister body is fixed on the front side of a rear fender, while a drain filter (filter box) connected through a drain pipe (drain passage) with the canister body and a discharge pipe are installed on the rear side of the rear fender. The cleaned air after the fuel vapor is adsorbed and removed is discharged into the atmosphere through this discharge pipe.
In the case of the canister system indicated by Japanese Utility Model Registration No. 2582688 and Japanese Laid-open Patent Application No. HEI9-49460, no fuel vapor flows into a passenger room and no water comes into the canister body in case the vehicle floor is flooded with water because the canister body is located higher than the vehicle floor.
The canister system disposed under the front seat floor of a vehicle is attached in a so called center tank vehicle in which the passenger room of the rear seats is made relatively spacious and the center of gravity is located relatively low, while a fuel tank is installed under the front seat floor, as indicated by Japanese Laid-open Patent Application No. 2005-313667. Especially in the case of the center tank vehicles equipped with On-board Refusing Vapor Recovery ( to be abbreviated as ORVR hereinafter) capable of recovering fuel vapor, a canister body is installed adjacent to and in the vicinity of the fuel tank and connected with a fuel tank through a vent pipe (communication pipe). Thanks to this configuration, the fuel vapor generated from inside the fuel tank is adsorbed on the adsorbent and the air communication resistance between the fuel tank and the canister body is reduced. Moreover a drain pipe is attached to the canister body to take in air from the atmosphere when purging the canister body to have the adsorbed fuel sent to an engine.
However there is an drain opening located at a relatively low position under the vehicle floor in the case of the center tank vehicle equipped with ORVR, which is described in Japanese Laid-open Patent Application No. 2005-313667. Through this drain opening such water as from rainwater and dirt and dust are easily absorbed together with air from the atmosphere into a canister system. As a result, there is a problem with a drain filter being easily clogged.
The present invention is to solve the aforementioned problem and intended to provide the drain pipe in the canister system which is installed under the front seat floor of a vehicle, prevent the air after fuel vapor is adsorbed and removed from flowing into a passenger room and inhibit water, dirt and dust being absorbed into a drain filter.